> After a short search I could not find the G3RUH circuit
> although I'm sure I've seen it before somewhere.
http://www.amsat.org/amsat-new/archive/index.php?t=./articles/James_Miller
You want the figures for, and the article, "9600 Baud Packet Radio Modem
Design"
> As I said, it's a modem implementation issue :-)
>> > James is a very careful engineer, and he did some pretty extensive
> > work with all this when he designed the modem and specified the
> > required passband response. The BER goes up pretty quickly
> > as the LF response of the system degrades.
>> If he noted that the LF demands are increased compared to
> plain old HDLC, why didn't he care to fix it?
He was making a modem compatible with the K9NG modem, so the scrambler
algorithm and its place in the grand scheme of things were already
constrained.
73,
Lyle KK7P